The present invention concerns an impact energy absorption system, in particular for motor vehicles.
Different impact energy absorption systems for vehicles currently exist.
Some systems use completely metallic cross members, generally made of steel, positioned between the vehicle chassis and the bumpers, while others use buffers, which are located between appropriate side members or struts of the chassis and the bumpers.
In particular, as honeycombs are structures generally characterised by good impact absorption properties, they have been applied where it is necessary to reduce the effects of any impact on persons or means of locomotion (in particular to protect structural parts of motor vehicles).
Some recent impact absorption systems feature a composite alveolar structure embedded in a foamed resin deformable element, which is positioned between a cross member fixed to a side member or strut of the vehicle chassis and the external bumper.
The deformable element consists of the alveolar absorption structure and the foamed resin, while the honeycomb structure consists of a series of alveoli, joined together, in the shape of prisms with hexagonal section, made of aluminium and positioned corresponding to each chassis strut.
Said known impact absorption systems have numerous limits and serious disadvantages, however.
Firstly, for systems with completely metallic cross member, it is practically impossible to simultaneously comply with the different vehicle impact regulations specifically for relative speed values of 4 km/h (simulation of impact during parking) and 15 km/h; in this regard, it should be remembered, for example, that the impact test at 15 km/h is considered, in some countries, to be a reference for the definition of vehicle insurance premiums, in relation to assessment of the damage sustained in the tests.
Furthermore, it should also be pointed out that, in the impact tests at 15 km/h, the impact occurs on the front and rear sides of the vehicles, on a portion equal to 40% of their width.
Therefore, in absorption systems that feature the use of buffers corresponding only to the chassis struts, there can be permanent deformation of the metal cross members, near the longitudinal centre line axis of the vehicle, in the event of impact at a relative speed of at least 15 km/h unless particularly reinforced cross members are used, which are consequently very heavy and expensive. These systems also have a poor capacity for absorbing impact in a slanting direction with respect to the longitudinal axis of the vehicle.
In particular, since the alveolar structures or buffers are normally used only corresponding to the chassis struts, this means that, in the event of impact at 15 km/h, to contain the internal deformation of the deformable element and of the vehicle internal cross member (and, therefore, to avoid permanent deformation of the vehicle bodywork elements), the area of the resisting sections must be increased, with consequent increase in weight and total production costs.
The object of the present invention is, therefore, to eliminate the above disadvantages, producing a high-efficiency impact energy absorption system for vehicles.
Another object of the present invention is to produce an impact energy absorption system for vehicles which simultaneously complies with the requirements of the various regulations, in particular in relation to impact at 4 km/h and 15 km/h, difficult to reconcile with the known products.
Another object of the present invention is to produce a system that can withstand repeated impact at low speed (4 km/h) without requiring replacement of any of its components and the bumper.
Another object of the present invention is to indicate an impact energy absorption system for vehicles that avoids permanent deformation of the cross members and bodywork elements of the vehicles in the event of impact at 15 km/h.
A further object of the present invention is to indicate an impact energy absorption system for vehicles, in particular for motor vehicles, which is extremely efficient also for impact in a slanting direction with respect to the longitudinal axis of the vehicle.
Last but not least, a further object of the invention is to produce an impact energy absorption system that is simpler and safer and also efficient and extremely reliable with respect to the known absorption systems.
These and other objects, according to the present invention, are achieved by producing an impact energy absorption system for vehicles according to claim 1, which is here referred to for the sake of brevity.
Advantageously, the system subject of the present invention has more limited overall dimensions and is considerably cheaper and lighter than the traditional systems, while offering the same level of performance.
With the same overall dimensions and weight, in addition to production costs, the absorption system according to the present invention offers much better performance in terms of ultimate strength, stability of mechanical characteristics over a wide temperature range, greater efficiency during impact and ease of use.